In general, video codecs are similarly structured, but the detailed process for each structure can be different from one another. It is imperative that this difference be considered when creating a unified codec.
FIG. 1 shows a typical process of a unified codec based on the related art. FIG. 1 illustrates the operational principle of a typical intra-only unified codec, focused on MPEG-2, MPEG-4 and AVC Intra coding.
Referring to FIG. 1, the process consists of, in the sequential and functional order, parsing and entropy decoding S100, data-reordering S110, inverse scan S120, inverse DC/AC prediction S130, inverse quantization S140, inverse transform S150, inverse intra-prediction S160, memory for decoded samples S170 and deblocking-filter S180.
As described above, the unified codec of the related art is simply divided by the function or the order of process, and each step is structured to process in detail according to the codec. Since functional units are pre-assigned to each codec, the user has only been allowed to use the functional units provided by the codec corresponding to the pertinent standard once the user selected a standard.
Although the unified codec of the related art unified a number of video codecs, one fixed codec had to be used to encode/decode one video.